qcacmn: Set max EHT rate set to 4
802.11BE D1.0 9.4.2.295c.4 Supported EHT-MCS And NSS Set
field specifies maximum 4 optional EHT MCS map, which are
20 MHz-Only STA, BW <= 80 MHz except 20 MHz-Only STA,
BW = 160MHz and BW = 320 MHz.
Therefore set WMI_HOST_MAX_EHT_RATE_SET to 4.
Also add a debug message to log peer_flags_ext.
Change-Id: I3d56998bf0de381ef147d6c0551dcdb7fd935f60
CRs-Fixed: 2963536